BRPI1016104B1 - MILK PRODUCT AND PROCESS - Google Patents

Abstract

method for preparing a dry modified whey protein concentrate (wpc) or whey protein isolate (wpi), a yogurt, a cheese concentrate, a whey protein hydrolyzate and for increasing the protein content of food kinds. The present invention relates to a method for preparing a modified whey protein concentrate (WPC) or whey protein isolate (WPI) is described. it involves supplying an aqueous solution of wpc or wpi having a protein concentration of 15 to 50% (w/v), at a pH of 4.7 to 8.5; (b) heat treating the solution reaching 50°C for some time, which allows denaturation of the protein to occur; heat treatment comprising heating the solution while under turbulent flow conditions. At the end of the heat treatment, the heat treated material can be readily transferred to a dryer or mixed with other ingredients. heat treated wpc or wpi are not subjected to a mechanical shearing process before transfer other than the liquid which is converted into droplets to facilitate drying. modified wpc is useful in beverage food production where a high protein content is desired without undesirable changes in texture.

Description

FIELD OF TECHNIQUE

[001] The present invention relates to a process for creating a whey protein concentrate (WPC) comprising denatured whey proteins.

BACKGROUND OF THE TECHNIQUE

[002] Heat-denatured whey protein aggregates have been produced for many years. Lactalbumin has long been known as a commercial product prepared from whey by heating until the protein coagulates and becomes insoluble. The insoluble material is filtered, washed and dried. Lactoalbumin has many uses that range from food reserve to increasing the protein content of bakery products and bread. The flow of protein-depleted whey that results from lactalbumin recovery can also be used as a food reserve, but it is an expensive way to dispose of it.

[003] Many attempts have been made to make the production of denatured whey protein both more economical and more commercially useful. Most of the effort was directed at increasing the protein content of whey by selectively removing the lactose content. High protein contents are enabled by the application of established technologies such as ultrafiltration, diafiltration and ion exchange. As proteins with good nutritional value, these products are useful as food ingredients.

[004] For many nutritional applications, the effect of whey protein on the texture or rheology of the final product is useful. These applications often depend on the ability of WPCs to form heat-induced gels. In other applications, these gelling properties are undesirable.

[005] Heat-denatured (or modified) whey protein products have become a newer category of products on the market. Several methods for producing this category have been invented in recent years.

[006] Whey protein will form a gel when heated under appropriate conditions (> 75 0C, ~ pH 6 to 8, > 6 g TS/100 g) (Havea, P., Singh, H., Creamer, L. K. & Campanella, O. H., Electrophoretic characterization of the protein products formed during heat treatment of whey protein concentrate solutions. Journal of Dairy Research, 65, 79 to 91, 1998).

[007] In US 4,734,287 (Singer et al.) there is a review of the heat-denatured whey protein technique that is particularly aimed at the production of insoluble aggregates and the problems associated with them. A process is taught to produce micro-particulate whey protein aggregates using a combination of heat and mechanical action. The document in its entirety is included by reference.

[008] In WO/2001/005247 [Hudson et al] disclose a process for preparing whey protein gels that include denatured particles. Initially the whey protein is treated to hydrolyze it using acids or enzymes. After heat treatment, with the resulting turbidity, particulate gels have an opaque milky appearance and a white appearance due to large aggregates that scatter light. Mixed gels, the final subset, have physical and functional properties of both full-bodied and particulate media, and are produced with intermediate salt concentrations (E. Foegeding et al., (1998)). Condensation of linear ribbons into larger aggregates is thought to be the causal mechanism of mixed gel formation. The gelled material can be dried to produce particles ranging from 1μm to 100μm. Hudson et al, teach little about their heating process (home production is contemplated) other than heating the dispersions in aluminum freeze-drying pans (13.5 cm x 13.5 cm) at 80°C for 45 minutes or 3 hours...

[009] Huss and Spiegel in US 6,767,575 disclose a process for producing microparticulate whey protein using relatively dilute protein streams (< 3% protein w/v), after heating and in contrast to processes known to those skilled in the art, no additional shearing operations are performed, to the extent that the process of the invention is performed under essentially non-shearing conditions. The shear rates occurring due to the unavoidable pump extraction and stirring operations mentioned are generally not greater than 2000 s-1 to 1000 s-1, preferably not greater than 500 s-1. Hot holding of the raw material can also be carried out in the complete absence of agitation.

[0010] WO/2007/039296 A1 [Thorsen and Koeningsfeldt] disclose a mechanical device for affecting the denaturation of protein solutions by applying heat.

[0011] In EP 0520581, Oudeman teaches a process of preparing a synthetic milk product using denatured whey proteins, in which calcium ions are added to a whey protein concentrate having a protein content of 25 at 50%, in relation to solid bodies, and a pH value of 5.9 to 6.7, the concentrate is subsequently subjected to heat treatment and homogenization, where after the product is optionally evaporated and dried.

[0012] US 5,494,696 [Hoist et al] discloses a whey protein denaturation process where the diluted whey retained (10 to 20% solids and 65 to 95% of the solids is protein) it is recycled through a homogenizer while being directly heated by steam injection. Note that: the flow rate of the product through the tube must be kept sufficiently high to avoid deposits on the tube walls and to ensure a sufficiently low viscosity of the pseudoplastic liquid. Generally, this is ensured when the flow rate is at least 2m/s. Directly after heat treatment, the liquid flux is dried. The resulting powder is said to have particle sizes of approximately 30 to 60 μm. Hoist et al state: It is surprising that the new, partially denatured whey protein product with a denaturation level of preferably approximately 80% and an average particle diameter ranging from preferably 40 to 50 μm have such good organoleptic properties and are without any remaining gritty or gritty flavor, whereas denatured whey proteins with similar particle sizes, as known, because of their poor organoleptic properties, particularly their gritty mouthfeel, are unsuitable for use as an additive to mayonnaise that is produced cold.

[0013] US 2006/0204643 [Merrill et al] discloses a heat denaturation process of whey protein concentrates wherein: the initial slurry containing native whey protein is heated to denature at least some of the protein . As noted above, the slurry can be heated to a temperature of approximately 60°C to approximately 93.33°C over a period of approximately 10 to approximately 60 seconds. The slurry may be mixed during at least a portion of the heating period to reduce, and/or prevent, denatured whey protein from coagulating around the heating elements in the cooker. An example device for performing this operation is a single mixer or twin screw mixer or a twin screw extruder, set for steam injection or having a heated jacket, or a combination of both. When using a twin screw mixer or extruder to perform heating and mixing, the screws (i.e. spirals) are typically mounted so overlapping, to ensure complete mixing. During or after heating, the slurry is subjected to high shear conditions, which reduces clots that may have formed with denatured whey protein. High shear conditions as used here generally refer to conditions in which 10,000 to 500,000 s-1 of shear are applied. In some methods, the slurry is typically sheared by a high shear mixer or colloid mill, at a temperature of approximately 32.22°C to 149°C for approximately 0.01 to 0.5 seconds.

[0014] In another invention, WO 2008/063115 A1 [Tetra Laval Holdings & Finance SA] disclosed a process where a protein solution is heated using a tubular heater under pressure (40 to 80 bar) followed by mechanical shearing in a homogenizer to break down aggregates of protein particles to form fines (3 to 10 µm diameter).

[0015] In two other publications (EP 0412590 & EP 0347237) [both intended for Unilever] processes are disclosed for preparing micro-particulate whey protein dispersions. In both publications, very little or no shear is used but the protein concentration is limited to relatively dilute solutions (less than 15% but preferably approximately 7% protein).

[0016] WO2006057968 (Wolfschoon-Pombo [Wolfschoon-Pompo] et al) discloses a cream cheese process where a stream of whey protein concentrate of 11 to 12% protein is heat treated in a tubular heater using turbulent conditions to produce a flow of particles of which 90% (d90) are smaller than 95μm and half of the particles (d50) are smaller than 12μm. Additional shear can then be applied (homogenization) to achieve considerably finer particles with d90 <9μm.

[0017] In DD236449, Borgwardt et al disclose that whey protein concentrate solutions with a protein content of 8 to 11%, solids content of 16 to 22% and pH of 4.2 to 5, 2, can be treated by heating at 85 to 95 ° C for 5 to 20 minutes under turbulent flow conditions to produce thermally stable non-caking colloidal whey protein suspensions. The suspension is stabilized by instantaneous cooling. The protein particle suspension can be dried. Borgwardt also teaches that although the Reynolds number must exceed 2000, wall shear stress must also exceed 12kg/ms2. The technique teaches that heat-treated protein slurries are shear thin (pseudoplastic liquid). For a person versed in hydrodynamics, it is unclear how to interpret (requiring implementation) Borgwardt et al's shear stress condition without more detailed information on the flow characteristics of their fluid.

[0018] It is an object of the present invention to provide a simple process of preparing denatured whey protein at high protein concentration; and/or provide a method of producing denatured whey protein products in high concentrations without the need for a homogenizer or scraping heat exchanger surfaces; and/or offer the public a useful choice.

DESCRIPTION OF THE INVENTION

[0019] In one aspect the invention provides a method for preparing a dry modified whey protein concentrate (WPC) or whey protein isolate (WPI), comprising: (a) providing an aqueous solution of WPC or WPI having a protein concentration of 15 to 50% (w/v), at a pH of 4.7 to 8.5; (b) treating the solution with heating to greater than 500C, for some time allowing protein denaturation to occur; heat treatment comprising heating the solution while under turbulent flow conditions preferably with a Reynolds number of at least 500; (c) at the end of the heat treatment, transferring the heat-treated material directly to a dryer; and (d) drying the heat-treated WPC or WPI, wherein the heat-treated WPC or WPI is not subjected to a mechanical shearing process prior to drying where the liquid is converted into droplets to facilitate drying.

[0020] In a further aspect the invention provides a method for preparing a heat-treated whey protein concentrate (WPC) or whey protein isolate (WPI), comprising: (a) providing an aqueous solution of WPC or WPI having a protein concentration of 15 to 50% (w/v), at a pH of 4.7 to 8.5; (b) the heat that treats the solution, at more than 500C for a period of time that allows denaturation of the protein to occur; the heat treatment comprising heating the solution while under turbulent flow conditions preferably with a Reynolds number of at least 500. Preferably in this aspect the process is followed by step (c): (c) at the end of the heat treatment which directly transfers the heat-treated material to a dryer to be dried or to a mixer to be mixed with other ingredients; and heat treated WPC or WPI is not subjected to particle size reduction prior to step (C).

[0021] In a further aspect the invention provides a method for preparing a dry modified whey protein concentrate (WPC) or whey protein isolate (WPI), comprising: (a) providing an aqueous solution of WPC or WPI having a protein concentration of 15 to 50% (w/v), at a pH of4.7 to 8.5; (b) treat the solution with heating to greater than 500C, for a period of time that allows denaturation of the protein to occur; heat treatment comprising heating the solution while under turbulent flow conditions preferably with a Reynolds number of at least 500; (c) at the end of the heat treatment, promptly transferring the heat-treated material to a dryer; and (d) drying the heat-treated WPC or WPI, wherein the heat-treated WPC or WPI is not subjected to a mechanical shearing process prior to drying or where the liquid is converted into droplets to facilitate drying:

[0022] In another aspect the invention provides a method for preparing a mixture comprising a liquid whey protein concentrate (WPC) or whey protein isolate (WPI), comprising: (a) providing an aqueous solution of WPC or WPI having a protein concentration of 15 to 50% (w/v), at a pH of 4.7 to 8.5; (b) treat the solution with heating to greater than 500C, for a period of time that allows denaturation of the protein to occur; heat treatment comprising heating the solution while under turbulent flow conditions preferably with a Reynolds number of at least 500; (c) at the end of the heat treatment, transferring the heat treated material directly to a mixer to be mixed with at least one of other ingredients, including at least one of the group consisting of milk, skimmed milk, fat, a carbohydrate, concentrate dairy, or skimmed milk concentrate; wherein the heat-treated WPC or WPI is not subjected to a mechanical shearing process before mixing with other ingredients.

[0023] Preferably the pH of the WPC concentrate before heating is adjusted between 5.0 and 8.5, more preferably between 5.5 and 8.5 and most preferably 6.0 and 8.0, most preferably 6 .5 to 7.5.

[0024] Preferably the protein concentration of the WPC concentrate before heating is 16 to 40%, more preferably 17 to 30%.

[0025] The WPC concentrate before heating can be adjusted to its calcium concentration. Calcium adjustment may include depletion i.e. ion exchange by any convenient process, or may be increased by the addition of a calcium salt e.g. calcium chloride.

[0026] The heating medium is preferably steam or heated water.

[0027] In preferred embodiments of each aspect of the invention, heat treatment occurs as the WPC or WPI solution passes along a heated flow path, preferably a tube with an inner diameter greater than 5 mm and less than 150mm.

[0028] In preferred embodiments a long tubular thermal reactor is used. Typically, the thermal reactor has a length based on its nominal retention time of between 1 second and 1000 seconds.

[0029] The temperature of the solution at the end of the reactor can be between 45°C and 1500C, preferably between 500C and 1300C and more preferably between 600C and 1100C.

[0030] The thermal reactor can be fed using a pump with a pressure rating between 0.3 MPa and 100 MPa (3 bar and 1000 bar), preferably between 0.5 MPa and 50 MPa (5 bar and 500 bar) and more preferably between 1 MPa and 35 MPa (10 bar and 350 bar). A supplementary pump may be useful to power the high pressure pump.

[0031] In some embodiments the product leaving the flow path is used as an ingredient in the preparation of a food product.

[0032] In other embodiments the flow path provides a dryer to convert the solution containing denatured whey protein complex into a dry product.

[0033] In a further aspect, the invention provides a method for preparing a dry modified WPC or WPI with at least 20% (w/w) of the TS as whey protein, preferably at least 40%, more preferably above 50%, and even more preferably 50 to 95% protein, most preferably comprising 52 to 90%,: (a) preparing an aqueous WPC or WPI having 15 to 50% (w/v) whey protein of milk, preferably 16 to 40%, even more preferably 17 to 30%, and most preferably 17 to 25%, at a pH of 4.7 to 8.5, preferably 5.5 to 8.5 and most preferably 6, 0 to 8.0, most preferably 6.5 to 7.5; (b) using a high pressure pump to feed the protein concentrate at a pressure between 0.3 MPa to 100 MPa (3 to 1000 bar), preferably 0.5 MPa to 50 MPa (5 to 500 bar), as well more preferably 1 MPa to 35 MPa (10 to 350 bar) in a high pressure heater, the product flow is such that a turbulent flow is effected preferably with a Reynolds number of at least 500; (c) heat treating the solution reached more than 50°C, preferably more than 60°C, more preferably more than 70°C and most preferably more than 80°C, for some time allowing denaturation of the protein to occur; (d) at the end of the heat treatment, promptly transferring the heat-treated material to a dryer; and (e) drying the heat-treated WPC or WPI, wherein the treated WPC flux of the heat treatment arrangement (c) is not subjected to a particle size reduction procedure prior to drying.

[0034] Preferably, the heat treatment zone is connected directly to the dryer inlet.

[0035] A "WPC" is a fraction of whey from which lactose has at least partially been removed to increase the protein content to at least 20% (w/w). Preferably the WPC has at least 40%, more preferably at least 55% (w/w), even more preferably at least 65% and most preferably at least 75% of the TS as whey protein. Preferably, the proportions of the whey proteins are substantially unchanged from those of the whey from which the WPC is derived. Preferably, the WPC is a retained evaporated whey protein. For the purposes of this specification, the term "WPC" includes WPIs when the context permits.

[0036] A "WPI" is a WPC having at least 90% of the TS as whey protein.

[0037] In another aspect of the invention, the invention provides products of each method of the invention.

[0038] In this specification the term "retained" means the fraction preserved after ultrafiltration of whey or a source or whey, milk or skimmed milk. Such fractions have increased percentage of protein and lower percentage of lactose as total solids than does the starting material.

[0039] The term "directly" in the context of material that is transferred directly means that the material is transferred from the heater to the next named step without any intervention processing.

[0040] The term "promptly" means for less than 2 minutes, preferably less than 1 minute, more preferably less than 30 seconds, much more preferably less than 10 seconds.

[0041] The term "comprising" as used in this specification means "consisting at least in part of". Interpreting each statement in this specification that includes the term "comprising", features other than this or those prefaced by the term may also be present. Related terms such as "understands" and "understands" should be interpreted in the same way.

[0042] Various methods can be used to estimate the level of denaturation (%) or determine the denatured protein (%) depending on the context of the experiment. For the production of colloidal particles from insoluble whey protein, the simplest method is to measure the proportion of the initial protein that has been rendered insoluble (separate by decantation as a precipitate) at pH 4.6. More detailed information on denaturation can be obtained by HPLC methods - see Huss and Spiegel in US 6,767,575, with this incorporated by reference in its entirety.

[0043] WPC starting material cannot be prepared by ultrafiltration of a crude whey at a pH of approximately 4.0 to 6.4, preferably pH 4.0 to 6.2, more preferably pH 4.0 to 6 .2 and most preferably pH 4.6 to 6.0. Using ultrafiltration, water, lactose and minerals are removed, resulting in retained flow. Diafiltration can be applied during ultrafiltration to also reduce the level of dialyzable components. Ultrafiltration is typically performed at 10 to 500C. Ion exchange can be used to manipulate the ionic content of the protein flow. The level of calcium ions can be manipulated in some embodiments by ion exchange and replaced with monovalent cations. In other embodiments, the calcium level can be increased by adding a soluble food approved calcium salt e.g. calcium chloride. The protein concentration of the WPC is preferably also increased by evaporation. Alternatively, the starting material may be a reconstituted whey protein prepared from a dried WPC or WPI.

[0044] The whey in the WPC preparation is preferably acidic whey or cheese whey. Acidic whey has a pH of approximately 4.6, while cheese whey has a pH of approximately 5.6 to 6.4. The pH of the concentrate upon heating can be varied depending on the desired functional properties of the final modified whey protein concentrate or powder. Those skilled in the art would know that heat treatment of whey protein under different pH would result in modification of protein-protein interactions in the heated system, giving rise to end products with varying functional properties. (Hudson et al in WO/2001/005247 discuss some of the technique of manipulating the properties of whey protein streams as they relate to their denaturation/gelation characteristics.)

[0045] The concentration of whey protein or WPC for the purposes of this specification is determined using the Kjeldahl nitrogen analysis method and the application of a Kjeldahl factor of 6.38.

[0046] The use of a high-pressure tubular heater is preferred as a flow channel, mainly because of its simplicity. Heating time varies depending on the temperature used. At higher temperatures, for example 1000C, only a few seconds may be needed. At 70°C, heating for a longer period may be necessary. It is also important to note that the degree of heating is a way of modifying the functional properties of the final powder. In different food applications, a wide range of modified WPCs with varying levels of protein denaturation may be necessary, and the present invention provides a simple means of creating these, only by modifying the protein concentration, pH, ionic environment, time heating temperature and/or heating temperature.

[0047] The "high pressure heater" refers to a shell and tube heater into which the product is fed through a tube that is surrounded in a heating chamber (shell). As the product is fed through the tube, the heating medium, which is preferably steam or water, is fed into the heating chamber. Preferably, the WPC is fed into the heating pipe using a high pressure pump.

[0048] Depending on the intensity of heating required, the heating medium (e.g. steam) can be pressurized to achieve higher heating temperatures. Those skilled in the art would appreciate that there are other forms of heating systems that can be used to achieve the same end result; Other heating methods may include ohmic and microwave etc. Direct steam injection is a preferred heating method.

[0049] Spray drying is currently preferred. Preferably, the heat treatment zone is connected directly to a spray dryer fitted with a nozzle or a group of nozzles or a rotary atomizer or an ultrasonic atomizer for the purpose of producing a stream of droplets.

[0050] The heat treatment should normally be of sufficient duration to denature a proportion of the whey proteins into insoluble aggregates. Preferably, the heat treatment is at least 600C and more preferably at least 700C. 700C to 1500C is a preferred range. More preferably, the solution is heated to 75 to 900°C. However, lower temperatures may be used (e.g. 50 to 700C and preferably 60 to 700C). Heating times vary depending not only on the temperature but also on the protein content, lactose and ion content. Typically, the heating time is 30 s to 15 minutes at temperatures ranging from 70 to 800C, 10 s to 10 minutes at temperatures ranging from 80 to 900C and 1 s to 5 minutes at temperatures ranging from 90 to 1000C. At higher temperatures, for example with steam injection, times can be reduced to, for example, 1 to 10 s. Preferably at least 30% (w/w), more preferably at least 50%, even more preferably at least 70%, much more preferably at least 80% of the denaturable proteins are denatured. Percent denaturation in the context of this specification means the percentage as determined by HPLC and the calculation of peak area reduction for undenatured whey proteins relative to those of unheated controls. This method is described in United States Patent No. 6,767,575.

[0051] A feature of the present invention is that whey protein concentrate, in high total solids (e.g. > 20%), is heated under turbulent flow. Because of the turbulent flow, the heat transfer coefficient is very high, resulting in rapid heating. Effectively, the process of the present invention offers a very efficient way of producing microparticulate whey protein products.

[0052] Turbulent flow is defined as sufficient mass flow rate in the heating tubes to provide a Reynolds number greater than 500, more preferably greater than 1000, even more preferably greater than 1500, and most preferably greater than 2000. Such Reynolds numbers are a characteristic of turbulent flow and are known in the art of hydrodynamics. The determination of the Reynolds number depends on the mass velocity of the fluid and its viscosity, which is defined as the nominal viscosity determined using the Hagen-Poiseuille equation from a measurement of the pressure drop along a known length of the horizontal pipe section. known uniform circular cross section at a known flow of heat treating the fluid at a uniform temperature before it is dried. A Reynolds number ranging from 2,000 to 50,000 is preferred for use in the invention, preferably from 5,000 to 30,000.

[0053] The term "not subjected to a mechanical shear process" means that the material is not subjected to a process in which a mechanical device, such as a grinding to homogenize colloid, high pressure pump, scraped the heat exchanger surface, high shear mixer or the like are used to mix the solution or break up particles within it.

[0054] The products of the invention have a wide range of usefulness. They can be used in applications where a high protein content is necessary but without incurring undesirable changes in the texture of the product to which they are added. The WPCs of the invention are suitable for use in processed cheese, yogurt and whey crisps (WO/2006/019320). The WPCs of the invention are useful in applications where the addition of high levels of whey protein without undesirable alteration of final product qualities may be necessary. The present WPC allows for the incorporation of whey protein into snacks and convenience foods without producing undesirable textures or flavors. For example, WPC can be used to add protein to the ingredients of a light bar meal that also comprises a source of carbohydrate and fat. Such a light meal bar can be prepared by melting fat, if melting is required, and mixing fat or oil with the carbohydrate and WPC and then leaving the mixture to settle.

[0055] The advantage of the process of the present invention is that it has only a simple heating step in addition to the standard processing of milk protein flow methods. Those skilled in the art would understand that the ability to heat treated whey protein at high TS is highly desirable for economic reasons.

[0056] One use of the invention is to produce yogurts with high protein content. The process comprises preparing a high protein yogurt milk having at least 7% (w/v), preferably 8 to 20% (w/v), more preferably 10 to 16% (w/v) protein by mixing a dry WPC or WPI of the invention with a milk comprising casein, and acidify the high protein yogurt milk to a pH of 3.8 to 5.5, preferably 4.0 to 5.0, much more preferably 4. 2 to 4.7. Also included are processes of preparing high protein yogurt drinks where the yogurt milk has a protein content of 1.5 to 15% (w/v), but with 30 to 90%, preferably 40 to 80% of the protein being whey protein of the invention.

[0057] Yogurt milk may include dry or liquid milk, dairy concentrate, milk protein concentrate (MPC), cream, or milk fat that are combined (with water if necessary) to form a reconstituted milk or a standardized milk composition. Skim milk is a preferred ingredient. Milk streams can be pasteurized as required by local regulations.

[0058] High protein yogurt milk is generally treated with heating before acidification, preferably at 70 to 1000C, more preferably 80 to 900C, much more preferably 85 to 950C, preferably for 5 to 20 minutes.

[0059] Acidification is most preferably carried out by fermentation using mixed cultures of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Cultures of Streptococcus thermophilus and any Lactobacillus species are also preferred as are cultures of Lactobacillus delbrueckii subsp. bulgaricus. Where acidification is by chemical acidification, the addition of glycono-delta-lactone is preferred.

[0060] "Yogurt" refers to an acidic or fermented food or beverage product prepared from a milk resource, and viable microorganisms or chemical acidulants or both. As the objectives of this yogurt of the invention also refer to yogurt-like products that may include dairy substitute lipids, flavorings and stabilizers approved by the food, acids and texturizers. Heat-treated yogurt and yogurt-like products are also included by the term yogurt. The term "yogurt" includes yogurts (set or stirred), yogurt drinks, and Petit Suisse.

[0061] The products of the invention are good substrates for producing whey protein hydrolysates with minimal particle content, with molecular weight greater than 20kD. Thus the invention provides a method of preparing a whey protein hydrolyzate comprising preparing a heat-treated WPC or WPI by the method of the invention and contacting it with a protease. Such hydrolysates have applications in nutritional compositions, including infant formulas.

[0062] WPCs and WPIs produced by methods of the present invention are also useful for preparing nutritional products, including nutritional drinks, and special nutritional products including meal replacement products.

[0063] Special nutritional products (sometimes known as medical foods and enteral foods) can be prepared for patients and elderly people and administered in liquid form. One of the challenges to be overcome in preparing such foods is achieving sufficient caloric density i.e. kcal/mL or kcal/g. At the densities of the art, the calories of such foods can range from below 0.5 kcal/mL to at least 3 kcal/mL.

[0064] A preferred embodiment of the invention comprises the sum of a heat-treated WPC or WPI prepared by a method of the invention or a hydrolyzate prepared by a method of the invention as an ingredient in a mixture to form a nutritional product that also comprises carbohydrate and water-soluble, preferably also comprising oil or fat. Preferably the mixture also comprises sodium and potassium salts and a source of lipids and vitamins. Preferably the mixture is heated to a temperature above 700°C, preferably above 1000°C, more preferably under at least commercial sterilization conditions. Preferably the mixture also includes a magnesium salt. Commercial sterilization conditions are conditions using the application of heat or high pressure to render a product free of microorganisms capable of growing on the product under the refrigerated conditions (above 100C) in which the product will be maintained during distribution and storage.

[0065] The ingredient of the invention was found to be surprisingly advantageous in the preparation of processed cheese, processed cheese foods and processed cheese-like foods.

[0066] A processed cheese can be prepared by a method comprising preparing a whey protein ingredient by the method of the invention, mixing the ingredient with other ingredients that include cheese and water, cooking to form a processed processed cheese, and allowing to cool down.

[0067] The invention consists of the foregoing and also visualizes constructions of which it gives only the following examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 shows a schematic layout of the whey protein heater reactor system

[0069] Figure 2 describes the relationship between apparent viscosity and retention time and treatment temperature combinations of 27% whey protein raw material

[0070] Figure 3 shows the relationship between the hardness of the bar (model nutrition bar samples prepared using the dry ingredient samples from the process of the invention and the particle size of the ingredient samples D [4,3] (μm ).

[0071] Figure 4 shows the relationship between the hardness of the feed bar model (as measured by penetration force) and the particle size distribution of the mud flow before drying as represented by D [4,3] ( μm).

[0072] Figure 5 shows the texture of the bar expressed as penetration force against heating temperature and tube time (s) property and perceived sandy in sensory informal (proportional to bubble size).

[0073] Figure 6 shows a schematic of the process for producing yogurts.

[0074] Figure 7 shows a schematic diagram of the high protein yogurt drink production process.

[0075] Figure 8 shows the viscosity in cP 100s-1 for Modified WPC before heating, after Modified WPC heating, Control WPC before heating and Control after WPC heating (from left to right).

[0076] Figure 9 shows photos of a nutritious food formulation before (I) or after (II) heating. A: formulation containing standard WPC; B: the formulation containing modified WPC; H: heated.

[0077] Figure 10 shows prepared particle sizes leaving the tubular reactor.

[0078] Figure 11 shows a graph of the percentage of denaturation against the exit temperature at different retention times

EXAMPLES

[0079] The following experiments also illustrate the practice of the invention.

EXAMPLE 1

[0080] Fresh cheese whey was prepared using standard commercial ultrafiltration / diafiltration techniques to produce a total solids retention of approximately 20%, of which 83% was protein. This concentrate stream was then adjusted to pH 6.9 using dilute NaOH and then the solids were also concentrated to approximately 33% using a pendant film evaporator to produce a concentrate with an outlet temperature of 450°C.

[0081] The hot concentrate (27% w/w protein) was fed at a flow rate of 6.3 mVh to two high pressure steam heated ladle and tube heat exchangers in series using a high pressure pump. pressure with a delivery pressure of 25 MPa to 30 MPa (250 to 300 bar), the concentrate leaves the first high pressure heater (length 60 m) at ~ 700C and leaves the second high pressure heater at 800C. The heater exchangers have a combined length of 120 m with an internal tube diameter of 18.85 mm. The steam pressure supplied to the first heater was 161.3 kPa (0.6 bar (g)) and the second heater pressure was 197.3 kPa (0.96 bar (g)). The high pressure piping was rated Schedule 80, alloy 316 stainless steel pipe.

[0082] After emerging from the second heater, the heat treated concentrate went through a trial period of either 0 s (no tube section), 45 s (54.8 m), or 90 s (107.3 m) of the 24 mm diameter tube. After the variable duration holding section, the heat-treated concentrate was transported to the nozzle stand above the spray dryer; This section of tube was approximately 56 m in length with an internal diameter of approximately 24 mm and provided an additional residence time of approximately 23 s. Thus the high-pressure pump released the flow of protein concentrate through the heaters and tube property (if present) to the dryer without the additional need for a mechanical shear inducing device. spray drying.

[0083] In the spray dryer, the heat-treated concentrate was delivered to a bank of 8 nozzles and was atomized into a droplet spray at a pressure greater than 20 MPa (200 bar). An inlet air temperature of 2100C and a chamber outlet temperature of approximately 83°C were used. The powder was also dried and then cooled in a vibrating fluidized bed prior to separating and packaging the material to produce a powder of approximately 3.5% moisture with a volume density of approximately 0.57 g/mL.

[0084] Figure 1 shows a schematic layout of the whey protein heater reactor system. The points at which system pressures were monitored are shown (DlPl, DP2 & DP3).

[0085] Wet and dry flow (product) particle sizes and particle size distributions (PSD) were determined using standard techniques and were conducted using a laser beam diffraction particle size analyzer, Mastersizer 2000, Malvern Instruments Ltd, Malvern, UK.

[0086] Nutrition bar samples (1 to 2 kilogram batches) were prepared and evaluated for hardness using a model recipe. The recipe comprised 37.3% heat treated WPC of the present invention (or used an undenatured WPC392 control, Fonterra), 34.4% Penford A2150 glucose syrup, 17.2% glycerin (Bronson & Jacobs Australia and supplied by Bronson & Jacobs NZ) 52.9% Maltodextrin, MALTRIN M180, DE 23-27, (GPC Grain Processing Co. USA and supplied by Salkat NZ) 5.1% hydrogenated palm kernel oil (Premium Vegetable Oils , Malaysia and supplied by Kauri NZ, Wellington), 0.5% lecithin (Cargill International and supplied by Bronson & Jacobs NZ), 2.6% water (w/w). The fat was weighed into a pan and melted on a hot plate at a temperature <40°C. The glucose syrup, glycerin, water and lecithin were weighed into a pot and heated to 55°C on the hot plate.

[0087] The protein powder and corn syrup solids were weighed and dry mixed together.

[0088] The liquids and melted fat were then added to the powder and mixed at 50 revolutions per minute using a BEAR mixer (Varimixer, 17584 BMS, Baker Perkins NZ) for 1 minute.

[0089] The mixer was stopped and the sides of the vat were scraped. The mixture was mixed for an additional 30 s until well combined.

[0090] The flour dough that was formed was then placed in a bar mold (dimension 600 mm x 330 mm x 16 mm), covered with plastic film and rolled in the mold, to adjust the structure. It was then allowed to sit overnight at room temperature.

[0091] The aggregate dough was then cut into bars measuring approximately 100 mm x 30 mm x 16 mm for storage testing, to produce 66 bars in total. The bars were placed in foil pouches, heat sealed, labeled and stored for one week at 200C before evaluation.

[0092] Figure 2 describes the relationship between apparent viscosity and combinations of retention time and treatment temperature of 27% whey protein raw material. It is known in the art that the denaturation of whey proteins by heat progresses sequentially via a chain of processes to ultimately produce insoluble aggregates which if allowed to reach a few tens of micrometer in size have a sandy texture in the mouth. Figure 2 depicts that when heat denaturation was conducted at very high protein concentrations (%), the process could be surprisingly controlled to reveal a new set of products at temperatures ranging from 65° to 800C with minute retention times. order one or less, and an additional set of new products at temperatures greater than 80°C and retention times less than approximately 120 s. Without being bound by theory, the higher (second) temperature set of products will probably also be associated with the formation of insoluble aggregates or colloidal particles of increasing size as heat treatment conditions progress. (Note that an additional retention time of approximately 23 s occurs after the experimental retention time in Figure 2, to convey the fluid into the dryer).

[0093] Figure 3 shows that the relationship between the hardness of the bar (model nutrition bar samples, after one week, prepared using the dry ingredient samples from the process of the invention) and the volume weighted average particle size of the ingredient samples D [4,3] (μm). As a separate variable, the plotted points in the figure represent the sensory texture (fraction rating) of the bar samples as given by the size of the circles. (Fraction assessment was determined by informal sensory use on a 1 to 9 scale, where 1-smooth, 3 powdery, 6 gritty, and 8 grainy.)

[0094] Texture analysis was performed using a TAHDplus Texture Analyzer DE Stable Micro Systems, Godalming, England.

[0095] Texture measurements were performed by compression. Forces were measured against set distance (mm). A 5 mm stainless steel cylindrical probe was pushed into the bar at a constant rate of 1 mm/s at a compression depth of 12 mm, and was then withdrawn at a rate of 10 mm/s.

[0096] Where possible, three compressions were made above the surface of each bar sample. Two bars were evaluated for each milk protein powder. Samples were removed from 200C storage and texture measurements were made at room temperature.

[0097] Surprisingly and considering the technique of products prepared using homogenization, Figure 3 describes that there was a group of process conditions in which it was possible to produce thick heat-aggregated whey protein particles, for example > 100 μm that did not were gritty in the mouth in a nutrition bar application without homogenization after or during heat treatment and before drying. The process conditions necessary to prepare this advantageous ingredient were then examined more closely.

[0098] Figure 4 shows the relationship between the model feed bar hardness (as measured by penetration force) and the particle size distribution of the mud flow before drying as represented by D [4,3]. The secondary variable plotted in figure 4 is the sand evaluation of the bar samples as indicated by the size of the circle. Generally, Figure 4 shows that the smoother bars result from larger colloidal particles that would generally be expected to be the result of more extensive heat treatments. However, Figure 4 indicates that there exists a new set of conditions from which an ingredient can be prepared (after drying) into coarse particles that do not result in a gritty mouthfeel as expected from prior art whey protein aggregates of size similar.

[0099] Bar texture expressed as penetration force against heating temperature and tube time(s) property and perceived sandy in sensory informal (proportional to bubble size). The control was a bar sample prepared using a non-heat treated (native) whey protein powder, WPC392 (Control 392), Fonterra Co-operative Group Limited, Auckland.

Grades:

[00100] Table 1d shows that when several sets of data are combined (Tables 1a, 1b and 1c), it is surprisingly described that there is a group of optimal preparation conditions of the denatured whey protein ingredient with unique properties of food applications. nutrition bar retention time < 45 seconds and a final curing temperature of 80° to 85°C, using the present heater design.

EXAMPLE 2

[00101] The protein ingredient of the invention was prepared using the previously disclosed method using a whey protein feed stream containing approximately 80% protein on a solids basis and a solids concentration of 32%, a processing flow rate of 6.4 m3/h, a high pressure preheater outlet temperature of 580C, a high final pressure heater outlet temperature of 800C and a residence time from the heater outlet to the dryer 23 seconds i.e. 0s pipe plant configuration property.

[00102] Tests were performed to establish the texture and sensory properties of the high protein yogurt using the heat denatured whey protein ingredient of the invention or a commercial native cheese whey WPC392 (Fonterra Co-operative Group Limited, Auckland, New Zealand) as alternative sources of protein fortification. These yogurts will be compared to standard 4.5% protein yogurt (3.5% protein from skim milk, 1.0% protein from top SMP).

[00103] Initial yogurt tests were performed using the ingredient of the present invention and WPC392 at high levels of addition (10 to 15% protein yogurts) to determine the basis of textural properties. When yogurt milk was heated using standard heat treatment (95°C/8 mm), the milk containing WPC392 coagulated and formed weak gels, and could not be further processed. Surprisingly, the protein ingredient of the present invention did not gel and was able to be used to prepare a high protein yogurt.

[00104] In other tests where WPC392 was used, it was added after the heat treatment step to reduce the potential of the added whey protein to gel.

Experimental Plan/Variables.

[00105] Table 2 details the superior formulations and ingredients of yogurts with high protein content. These are compared to a standard 4.5% protein (0% fat) sensory control yogurt.

FORMULATIONS

[00106] The formulations used are given in table 3a and the recipes in Table 3b Table 3a. Details of the formulations used in the tests. Table 3b. Recipes used to prepare the samples.

MANUFACTURING PROCESS

[00107] The ingredients (or else the culture) were dispersed in hot water and allowed to stand for a period to allow for proper hydration. The solutions were heated to approximately 550C and then homogenized at 15/5 MPa (150/50 bar). The samples were then batch heat treated in a water bath at 90°C for 10 minutes. The samples were cooled to the incubation temperature and the culture added and dispersed.

[00108] Fermentation times were considerably longer for yogurts with high protein content. Incubation was at 38°C for 15 to 16 hours. The stirred yogurt samples were sheared (smoothed) by pumping through a back pressure valve (BPV) or orifice with a pressure drop of 170 kPa (1.7bar) and at a temperature of 1 T.C.

[00109] See figure 6 of Yogurt Process Diagram.

RESULTS

[00110] A summary of all test data is given in table 4. Table 4. Summary of test results.

VISCOSITY

[00111] The viscosity of both 15% protein yogurts (3.5% SMP with 11.5% protein of the protein ingredient of the invention and 4.5% SMP with 10.5% of the protein ingredient of the invention) was approximately 590 mPa.s. Surprisingly, the viscosity was similar to a 4.5% protein yogurt (Table 4). The viscosity of the 12% protein yogurt (with 3.5% SMP base protein) was also lower than controls not of the invention.

SYINERESIS

[00112] The syneresis values of stirred yogurts are shown in table 4.

[00113] The syneresis values of the 12% protein yogurt (3.5% SMP-based protein) and the two yogurts containing WPC392 were very high (> 90%). The 15% protein yogurt of the invention and 12% protein yogurts (4.5% SMP base protein) were lower or similar to a standard 4.5% protein yogurt.

INFORMAL SENSORY

[00114] The samples were evaluated without formalities by 5 members of the cultivated food team. It was noted that the taste of the high protein yogurts of the invention had less of a "protein" taste than the samples containing WPC392.

EXAMPLE 3. High Protein Yogurt Drink with Low Viscosity.

[00115] The protein ingredient of the invention was prepared using the method of example 1 using a whey protein feed stream containing approximately 80% protein on a solids basis and a solids concentration of 32%, a processing flow rate of 6.4 m3/h, a high pressure preheater outlet temperature of 580C, a high final pressure heater outlet temperature of 800C and a residence time from the heater outlet to the dryer of 23 seconds this is 0 s pipe plan configuration property.

[00116] Tests were carried out to manufacture the high protein yogurt drink with the viscosity of the final product low enough to be consumed as a drink.

Experimental Plan/Variables. Formulations

[00117] The recipes are given in table 1. Table 5. Recipes for preparing the fermented drink.

Manufacturing process

[00118] The ingredients (or else the culture) were dispersed in hot water and allowed to stand for a period to allow for proper hydration. The milk was heated to approximately 55°C and 2 stages of homogenization at 15/5 MPa (150/50 bar). The homogenized milk was heated to 95°C for 8 minutes circulating in a plate heat exchanger (PHE) then cooled to the incubation temperature in an additional PHE and finally discharged into the small vat. The culture was added and dispersed and the milk was incubated at 420C until a pH of approximately 4.6 was reached.

[00119] The incubation time was approximately 5.5 hours. Despite the high protein content, the fermentation time was surprisingly typical for much lower protein yogurts (e.g. 4.6%).

[00120] The high protein yogurt drink was cooled to approximately 200C by pumping through a PHE, then sheared (smoothed) by passing through a back pressure valve (BPV) or orifice with a pressure drop of 0.3 MPa (3 bar).

[00121] See the diagram of the high protein yogurt drink manufacturing process in figure 2.

Results

[00122] A summary of the test results is given in Table 6.

Viscosity

[00123] The viscosity of the high protein yogurt drink was less than half that of control 4.5% (low fat) skimmed milk yogurt making the product surprisingly suitable as a yogurt drink.

EXAMPLE 4. Preparation of enzyme-treated hydrolysates.

[00124] A common recipe was used to evaluate five protein samples: the 80% undenatured whey protein concentrate (WPC) [control 1], and three denatured whey proteinates of the invention, T13, T14 and T21 and a fully denatured lactalbumin powder [control 2] - see below for details.

[00125] Other protein ingredients used were:

[00126] Lactoalbumin 8254 (control 2), available from Fonterra Co-operative Group Limited, Auckland. Lactalbumin 8254 is 100% denatured.

[00127] Sodium caseinate 180 available from Fonterra Co-operative Group Limited, Auckland.

[00128] WPC80 (WPC392) cheese available from Fonterra Cooperative Group Limited, Auckland. WPC392 is essentially native whey protein that is 0% denatured.

[00129] A range of denatured WPC powders of the invention (denaturation > 95%) were reacted with Alcalase and Thermoase (together) using the same recipe (1% Alcalase and 1% Thermoase) and the protein ingredients control whey samples known in the art that were used for the comparison were WPC392 and lactalbumin 8254.

[00130] Details of the hydrolysis recipe are given in table 7. Table 7. Recipe used for enzymatic hydrolysis of the protein ingredient.

[00131] Later added for pH adjustment: 940g of the RO water was heated to 650C in a water bath 60g of the protein ingredient was added to the water after 5 minutes with continuous stirring.

[00132] The pH was adjusted to pH 7.5 using NaOH and KOH if necessary at T = 0 min both Alcalase and Thermoase enzymes were added to the solution (pH 7.5 thermostat at 65°C)

[00133] The pH of the reaction mixture was maintained at 7.5 during the digestion course by adding alkali as indicated in table 3

[00134] Hydrolysis lasted for a total reaction time of 5 hours. The reacted solution was heated at 85°C for 20 minutes to inactivate the enzymes.

[00135] The molecular weight profile (MWP) was analyzed using the size exclusion chromatograph using the method disclosed in ANZSMS22 (Australia and New Zealand Society for Mass Spectrometry 22nd Annual Conference) Sydney, January 2009.

[00136] And then batches of hydrolyzate are prepared using the denatured dry ingredient WPC of the present invention (and a WPC392 control). The ingredient of the present invention advantageously gave a desired MWP, which is <1% of the material in the >20kDa region.

[00137] The same recipe (enzyme combination) was used for the hydrolysis of powders T13, T14 and T21. The ingredients of the present invention were prepared according to the heat treatment procedures specified below. T13 = 85°C 0s, no additional tube holding time Tl 4 = 900C 0s, additional tube holding time T21 = 85°C 45s, additional tube holding time

[00138] Details of the recipes are given in table 8. Table 8. Recipe used in additional hydrolysis tests

[00139] Various enzymes, including proteolytic enzymes, are used in the preparation of human nutrition products. Different nations have different regulations. The European Union appears to be developing regulations toward lists of specifically approved enzymes. ht1p://www.amfep.org/documents/A mfep%2009%2001%20%20Amfep%20Statement%20on%20Food%20 Enzymes%20Regulation%20%20FlAP%20- JAN09.pdf

[00140] With the objectives of demonstrating the beneficial and versatile results of the ingredient of the present invention when used as a proteolysis substrate, a selection of enzymes was selected to evaluate proteolytic efficacy.

[00141] The enzymes used were supplied by: Alcalase 2.4L - Novozymes Australia Pty. Ltd (www.novozymes.com), Enzidase TSP Concentrate (TSP) - Zymus International Ltd (www.zymus.net), Pancreatin - American Laboratories Inc (www.americanlaboratories.com), Thermoase PClOF - Daiwa Kasei K.K (Shiga, Japan).

[00142] The enzymes TSP and Pancreatin were used individually in replacement of the pair of enzymes used in table 7 to prepare an additional series of hydrolysates according to the details given in table 9. Table 9. Details of the enzymes and their reaction conditions .

[00143] Table 10 summarizes the MWP that results from hydrolysates prepared using the Alcalase and Thermoase combination detailed in table 7. Table 10. Comparison of denaturation levels and hydrolyzed MWPs resulting from reacted samples.

[00144] It is generally desirable that less than 1% of the peptide has a molecular weight >20kDa in hydrolysates designed for child formulas where claims of reduced antigenicity are made. The ingredient of the present invention was surprisingly able to meet this limit without the need for the extra treatment step, thus avoiding the loss of yield and expense of subsequent ultrafiltration. Tables 11 and 12 summarize the yield and processing problems typically presented by preparing hydrolysates using processes known in the art and compare these with the benefits that result from the invention. Table 11. Comparison of the ingredient yield advantage of the invention with commercial lactalbumin. Table 12. Comparison of ingredient yield advantages of the invention with existing commercial hydrolysates.

The hydrolysis of one of the powders of the above invention (T13) using different recipes (enzymes).

[00145] An additional series of hydrolysis reactions using the Tl of the invention 3 ingredient (96% denatured) and two different recipes (Pancreatin enzymes and TSP) was conducted with the results given in tables 13 and 14. Table 13. Results of the hydrolysis using the pancreatin enzyme.

[00146] The ingredient of the present invention when treated with Pancreatin gave a more preferred MWP that avoided the need for ultrafiltration to remove excess material >20kDa. Table 14. Hydrolysis results using the TSP enzyme.

[00147] The ingredient of the present invention when treated with TSP gave a more preferred MWP that avoided the need for ultrafiltration to remove excess material >20kDa.

[00148] Two additional hydrolysis reactions were conducted using the protein ingredient of the invention but modified to the point that the protein ingredient was obtained directly after the thermal denaturation procedure of the invention as an inert liquid stream (-90% denatured) and before drying, using different recipes (enzymes) and shown in Table 15. Table 15 also summarizes the results of hydrolyzing the liquid stream ingredient of this invention. Table 15. Hydrolysis results of the liquid protein stream of the invention

[00149] The non-dried ingredient version of the present invention (liquid flow) again gave a preferred MWP that avoided the cost of drying and the need for subsequent treatment to remove unwanted content > 20kDa.

EXAMPLE 5. Examples of nutrition Liquid / drink / enteral / medical foods.

[00150] Two following examples illustrate the use of the whey protein ingredient of the invention to prepare model beverages with special properties useful in various nutritional and medical foods. In one series the drink had a caloric value of 1 kcal/g. In the second series, the drink had a caloric value of 1.5 kcal/g.

[00151] For each of the calorific values, three formulations were examined: a) 95% of the protein denaturation heating of the present invention and 5% coming from sodium caseinate, b) a duplicate of the above, c) a control of 100 % heating denaturation of the whey protein powder of the present invention and no sodium caseinate.

[00152] 28 kg of demineralized water at 550C was weighed in the Cowles Solubilizer, the protein was added and mixed for 60 minutes

[00153] Maltodextrin and sucrose were added and mixed for 5 minutes

[00154] The minerals were pre-dissolved at 500C in a small amount of water and mixed for 5 minutes.

[00155] The mineral solution was added to the ingredients in the Cowles Solubilizer and mixed for 5 minutes. The solution was also heated.

[00156] The oil and lecithin were heated to aid dispersion and mixed in a separate reservoir

[00157] The oil lecithin mixture was added to the Cowles Solubilizer solution and completely dispersed.

[00158] The dispersed and the still hot solution were homogenized in two steps. The homogenized solution was cooled to 250C and the pH adjusted to target pH 6.8 with KOH.

[00159] Water was added to the solution to exceed what was necessary to give a final weight of 40 kilograms.

[00160] The solution was transferred to the UHT plant and UHT processed at 1400C for 4 seconds using direct steam injection heating was aseptically packaged in 250mL glass bottles and capped.

[00161] Various tests were conducted before and after UHT heat treatment.

Formulation type for 1 kcal/g nutritional food model.

[00162] Formulation (a) differed from formulation (b) in that a duplicate batch of the ingredient of the invention was prepared for use. Formulation (c) used in the second batch ingredient. The formulations are detailed in table 16. Table 16. Recipe formulation model for 1 kcal/g drink examples. Formulation type for 1 kcal/g nutritional food model.

[00163] The formulations used for 1.5 kcal/g assessments are shown in table 17. Table 17. Formulation and recipes for 1.5 kcal/g drink examples.

[00164] The results of the evaluation of samples prepared according to the formulations in tables 16 and 17 are shown in table 18. Table 18 results of 1 kcal/mL 1.5 kcal/mL

EXAMPLE 6. Use of direct steam injection to produce liquid whey protein stream heated under turbulent flow conditions that is useful as a protein ingredient

[00165] A protein concentrate solution was obtained by reconstituting a 25 kilogram cheese WPC 392 powder in 70 liters of chlorinated water. The WPC powder had 81% protein, 5.7% fat, 3.4% ash, 4% lactose, and 4% moisture. After reconstitution the whey protein solution was continuously mixed at 500C for 2 hours to allow complete hydration of the protein.

[00166] The whey protein solution (pH 6.8) was pumped through an experimental plant product line at 152.5 kg/h (~137.4 L/h, product density of 1.11 lcg/L) where it was heated by direct injection of steam at ~170°C and ~7 bar measurement via a steam injection valve. The product line was a 5 m long, 10 mm inner diameter stainless steel tube. The steam pressure was adjusted to between 5 and 7 bar measurements so that the product temperature was maintained at approximately 900C. The direct product flow to the DSI unit had a calculated Reynolds number of 599. The heated liquid was collected via the product valve ~5 m after the DSI point. It took ~3 s for the product to travel from the steam injection point to the collection point. The heated flow was 89.10C at the DSI outlet.

[00167] The heated flow was collected in a reservoir and became a semi-solid paste to cool to room temperature. This heated stream was used as a protein and water source in creating the model nutritional food formulation shown in table 19 below. A sample of the original WPC powder was used in the preparation of another sample of the nutritional food formulation as a control. Table 19. Recipe for a nutritional formulation model.

[00168] The preparation of the reconstitution involving the nutritional formulations of the protein ingredient with water at 550C for 30 minutes using an overhead shaker. Sucrose, maltrin, and minerals were added while mixing and after mixing continued for an additional 10 minutes. The mixture was heated to 700C then the oil (with the lecithin already dissolved in it mixing at ~700C) was added then mixing continued for an additional 10 minutes. The mixture was after two steps homogenized (200/50bar) using a bench top homogenizer (NIRO-SOAVI, Panda N. 2638, Niro Group, Parma-Italy). The homogenized formulation was then placed into 10 ml retortable glass bottles then heated at 1210C for 10 minutes in an oil bath. The heated samples were cooled immediately to 200C in cold water. The viscosity of the homogenized formulations before and after heating was measured using a Paar Physica rheometer (the model UDS200, Anton Paar GmbH, Graz, Austria) with a cone and plate geometry, shear sweep 0.1 at 500 s-1, at 200C. .

[00169] Figure 8 shows the effect of modified WPC on the viscosity of the model nutritional food formulation before and after heating (1210C, 10 minutes). The viscosity of both formulations before heating was similar. After heating, the viscosity of the formulation containing modified WPC increased to approximately 84 cP. The product of the invention remained a smooth free flowing drinkable product. However, after heating the control formulation contains standard WPC a gel had formed making viscosity measurement impossible.

[00170] Figure 9 shows photographs of the formulations before and after heating. It is clear that the formulation containing modified WPC remained a smooth free flowing liquid while that containing standard WPC formed a gel.

[00171] Nutritional formulations are used as meal replacements for a wide range of consumers to meet various nutritional and/or lifestyle requirements. These foods are touted to provide full nutritional requirements in small drink packages. As such they often contain high fat, carbohydrate, and protein such as those in the model formulation given in table 19 above. Its processing always involved intense heating treatment (e.g. 1210C for 10 minutes) because of the need to be microbiologically safe. In such heat treatment it is important to have robust ingredients that are able to withstand the intense heat treatment conditions without gelling or forming solid lumps. This example demonstrated that using the heat of the invention modified WPC of the present invention permitted addition of whey protein at high level (>9%) in a nutritional formulation that remained smooth liquid (low viscosity) after its treatment. with final product heat.

EXAMPLE 7.

[00172] This study was performed using a Rapid Viscosity Analyzer (RVA 4). An individually wrapped slice (IWS) processed cheese formulation containing 4% of either cheese whey derived from WPC 392 (80% protein) or the heat denatured whey protein ingredient of the invention was used to the comparison. The firmness and meltability of the resulting products were measured along with their composition and microstructure.

Goals

[00173] Compare the performance of standard whey protein concentrate (WPC) 392 and the invention's heat denatured whey protein ingredient by: 1. Making the IWS processed cheese in an RVA using the two concentrates. whey protein. 2. Comparison of the properties of the resulting processed cheese samples.

Methods and Materials

[00174] Two processed cheese slice formulations were manufactured in a Rapid Viscosity Analyzer (RVA). The processed cheese formulation from a simple model IWS was used which contains ~4% WPC392 or the heat of the invention denatured the whey protein ingredient. Run 1 contained the standard WPC392 and Run 2, the heat from the invention denatured the whey protein ingredient. Actual formulations are tabulated in Table 20. Table 20. Formulations used to prepare samples

[00175] The methods used in this work were taken directly from the published PCT patent application WO 2007/108708 Al (Ardil, Sotavento, Anema and Havea)

Mixture

[00176] Rennet casein, WPC, trisodium citrate, salt and water were mixed together and left to hydrate for 40 minutes in an aluminum RVA can. The grated cheese, salted butter, lactose, citric acid and potassium sorbate were added and mixed.

Kitchen

[00177] The cheese mixtures were cooked at RVA for 10 minutes. The temperature was increased from 25°C to 87°C over the first 4 minutes and maintained for the remainder of 6 minutes at 870C. The stirring speed was increased from 0 to 800 revolutions per minute for the first 4 minutes and remained at 800 revolutions per minute for the remaining 6 minutes. In cooking, the hot processed cheese sample was poured onto a polypropylene sheet, covered with another polypropylene sheet, and rolled into a slice. The slice was sealed in a zip code lock plastic bag and quickly cooled on an aluminum tray in a refrigerator. 6 slices were made for each run. Viscosity was recorded on the RVA immediately before the formation of each slice.

[00178] Composition Moisture was analyzed using a conventional oven method (16 hours at 1050C). pH was measured using a Radiometric pH meter Standard PHM82 and N48 EE probe.

Texture Measurements

[00179] The slices were kept at 5°C for 3 days before testing. For the texture test, 4 slices were stacked together, cut in half, and the two halves stacked. So the experiment stack was 8 slices thick.

[00180] Firmness was measured using penetrometry (1/4" cylinder [6.4 mm]) on a TA-HD Texture Analyzer (aka Cylinder Test) at 13°C. The cylinder was inserted 10 mm into the slice stack, with a speed of 1 mm s-1 and the maximum force were recorded.4 measurements were taken.

[00181] Stress and strain were measured at 130C using a Grimpa Test (Brookfield 5XHBTDV-II viscometer). 6 mm, the laminated Grimpa 4 was inserted to a depth of 10 mm, and rotated at 0.5 revolutions per minute until the yield point was reached. 4 measurements were recorded.

[00182] Melts were measured using a Schreiber Melt Test (232°C for 5 minutes, Zehren and 1992 Nusbaum) Process Cheese. The Cheese Reporter Publishing company.

Results Composition

[00183] pH and humidity data are shown in table 21. The humidity and pH of the samples are very consistent. These differences mean that in texture properties merge, they will probably be due to differences in ingredient, performance rather than compositional variation.

[00184] Moisture evaporation occurs during cheese production in the RVA. Moisture was not adjusted for evaporation during processing as this is assumed to be constant between batches. The consistent humidity data in table 21 confirm this approximation. Table 21. Summary of results

[00185] Results are indicated ±1 standard deviation.

Final Viscosity

[00186] The average final viscosity is tabulated in table 21.

[00187] The final viscosity is clearly different with the processed cheese containing WPC392 higher than that of the invention containing heat denatured whey protein ingredient.

Firmness as measured by the Cylinder Test

[00188] The firmness results are recorded in table 21. The firmness of the IWS made from standard WPC392 appears to be lower than the IWS made from the invention's heat denatured whey protein ingredient. As the moisture and pH of the samples are almost identical (and the protein and fat content by inference) then the difference in firmness is due to the WPC ingredients.

Stress and strain results as measured by the Grimpa Test

[00189] Grimpa's stress results are tabulated in table 21. The stress data model matches the stress firmness data of processed cheese made from WPC392 that is lower than the ingredient of the invention.

[00190] The Grimpa strain results are tabulated in table 21. The strain data of the IWS made from standard WPC392 is lower than that made from the ingredient of the invention.

Fusion

[00191] The melting results are presented in table 21. The IWS made from standard WPC392 melts significantly less than that made from the ingredient of the invention. Summary IWS made with the ingredient of the invention melted more than the cheese made with WPC392 IWS made with the ingredient of the invention was firmer than the cheese made with WPC392 IWS made with the ingredient of the invention had the lowest viscosity in the process than cheese made with WPC392

[00192] The composition of the slices was relatively uniform (moisture and pH) as was the microstructure. This suggests that any textural differences are disturbances due to compositional variation.

EXAMPLE 8. Characterization of the liquid flow emerging from the high pressure tubular reactor before drying.

[00193] Figure 10 shows that very fine particle dispersions can be prepared except the tubular reactor of this invention.

[00194] Figure 11 shows that the point of denaturation can be finely controlled in the liquid flow emerging from the tubular reactor by adjusting the combinations of temperature and retention times.

Claims (17)

1. Method for preparing a mixture comprising a liquid whey protein concentrate (WPC) or whey protein isolate (WPI), characterized in that it comprises: (a) providing an aqueous solution of WPC or WPI presenting a protein concentration of 15 to 50% (w/v), at a pH of 5.5 to 8.5; (b) pressurizing the aqueous solution supplied into a flow path; (c) treating the pressurized solution with heat at greater than 50°C and less than 150°C for a time that allows denaturation of the protein to occur, wherein at least 50% of the denaturable proteins are denatured, said time being less than 120 s; heat treatment comprising heating the solution while under turbulent flow conditions with a Reynold number in the range of 2,400 to 50,000 and wherein the volume-weighted average particle size D[4.3] of the whey protein particles of milk in the pressurized solution is less than 10 μm and the pressurized solution is not subjected to a mechanical shear process to break up particles within the solution; and (d) at the end of the heat treatment, or (i) transferring the heat-treated material directly to a mixer to be mixed with at least one other ingredient, including at least one from the group consisting of milk, skimmed milk, fat, a carbohydrate, dairy concentrate, or skim milk concentrate, or (j)) transferring the heat-treated material promptly to a dryer and drying the heat-treated WPC or WPI; and provided that the heat-treated WPC or WPI is not subjected to a mechanical shear process in which a mechanical device is used to disrupt particles within the solution prior to either the optional drying step or the optional mixing step except when a mechanical shear in which the liquid is converted into droplets to facilitate drying. 2. Method according to claim 1, characterized by the fact that at the end of the heat treatment, the heat-treated material is transferred directly to a dryer. 3. Method according to claim 1, characterized by the fact that at the end of the heat treatment, the heat-treated material is transferred directly either to a dryer to be dried or to a mixer to be mixed with other ingredients; and wherein the heat-treated WPC or WPI is not subjected to particle size reduction prior to step (d). 4. Method according to claim 1, characterized by the fact that at the end of the heat treatment, the heat-treated material is promptly transferred to a dryer; and heat-treated WPC or WPI is not subjected to a mechanical shearing process prior to drying except when the liquid is converted into droplets to facilitate drying. 5. Method according to claim 1, characterized by the fact that at the end of the heat treatment, the heat treated material is transferred directly to a mixer to be mixed with at least one other ingredient, including at least one of the group consisting of in milk, skim milk, fat, a carbohydrate, dairy concentrate, or skim milk concentrate, where heat-treated WPC or WPI is not subjected to a mechanical shear process before mixing with other ingredients. 6. Method according to claim 1, characterized in that the pH of the WPC solution before heating is adjusted between 6.0 and 8.0. 7. Method according to claim 1, characterized by the fact that the protein concentration of the WPC solution before heating is 16 to 40%. 8. Method according to claim 1, characterized by the fact that the heat treatment occurs as the WPC or WPI solution passes along a heated flow path with an inner diameter greater than 5 mm and less than 150 mm . 9. Method according to claim 1, characterized by the fact that the solution passes along a heated flow path and exits at a temperature between 60° C and 110° C. 10. Method for preparing a yogurt, characterized by the fact that it comprises including a dry WPC or WPI prepared by the method, as defined in claim 1, as an ingredient in the yogurt. 11. Method according to claim 10, characterized by the fact that it comprises preparing a yogurt milk having at least 7% (w/v) protein by mixing the dry WPC or WPI with a milk comprising casein, and acidifying the yogurt milk. yogurt at a pH of 3.8 to 5.5. 12. Method for preparing a yogurt drink, characterized by the fact that it comprises 1.5 to 15% (w/v) protein comprising mixing a dry WPC or WPI prepared by the method, as defined in claim 1, with a milk comprising casein, and acidify to a pH of 3.8 to 5.5. 13. Method for preparing a whey protein hydrolyzate, comprising preparing a heat-treated WPC or WPI of the method as defined in claim 1, and contacting the heat-treated WPC or WPI with a protease. 14. Method for preparing a processed cheese, characterized in that it comprises: preparing a whey protein ingredient by the method as defined in claim 1, mixing the ingredient with other ingredients including cheese and water, cooking to form a processed processed cheese, and let it cool. 15. Method for preparing a dry modified WPC or WPI with 50 to 95% of total solids as whey protein, characterized in that it comprises: (a) preparing an aqueous WPC or WPI having 15 to 50% (w/ v) whey protein, at a Ph of 5.5 to 8.5; (b) use a high pressure pump to feed the protein concentrate at a pressure of between 0.3 and 100 MPa (3 and 1000 bar) into a high pressure heater, the flow of the product is such that a flow turbulent is carried out with a Reynolds number in the range of 2,400 to 50,000; (c) treating the solution with heat obtained at more than 70°C and less than 150°C, for a time that allows denaturation of the protein to occur, wherein at least 50% of the denaturable proteins are denatured, said time being less than 120 s; and provided that the pressurized protein concentrate is not subjected to a mechanical shear process in which a mechanical device is used to break up particles within the solution; (d) at the end of the heat treatment, promptly transfer the heat-treated material to a dryer; and (e) drying the heat-treated WPC or WPI, wherein the volume-weighted average particle size D[4.3] of the whey protein particles in the treated WPC stream from the heat-treating arrangement (c) is less than 10 μm and the particles are not subjected to a particle size reduction procedure before drying. 16. Method, according to claim 15, characterized by the fact that the heat treatment step (c) occurs in a heat treatment zone that is connected directly to the inlet of the dryer. 17. Method according to claim 15, characterized in that drying is by spray drying.